[dragonegg] r186952 - The debug info verifier requires a non-empty name here. Pacify it.

[Duncan Sands]

Hi David,

On 23/07/13 19:01, David Blaikie wrote:
> On Tue, Jul 23, 2013 at 9:08 AM, Duncan Sands <baldrick at free.fr> wrote:
>> Author: baldrick
>> Date: Tue Jul 23 11:07:59 2013
>> New Revision: 186952
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=186952&view=rev
>> Log:
>> The debug info verifier requires a non-empty name here.  Pacify it.
>
> If such debug info really doesn't need a name (I haven't looked at the
> code further to see which entity this code is for - a global variable,
> I guess) & we can/do support that (a test case would be good) we
> should just fix the verification not to complain about such a valid
> construct.

thanks for taking an interest.

It's like this: dragonegg produces debug info for this global variable because
it produces debug info for all global variables, not because I think it will
enhance someone's debugging experience.  However it seems pretty reasonable to
me that it should be possible to produce natural debug info for any global
variable.  In this case natural means without a name, since this variable is
really anonymous.  In the original source code it is the number 77, now sunk
into a global constant so it can have its address taken.  Still, it exists.

So my view, taken from 1000 miles up and from the planet of those who know
nothing about debug info, is that nothing should be required to have a name,
because sometimes things just don't have names.  For example, I already have
to create artificial names for types because otherwise the debug metadata is
rejected, but I don't like it.

If having no name means that the entity can't even be accessed in the debugger,
then maybe that metadata should be dropped *as an optimization*.  But not
rejected as wrong.

As I said, my view from a planet far far away from the land of those that
actually know something about debug info.

Ciao, Duncan.

>
>>
>> Modified:
>>      dragonegg/trunk/src/Debug.cpp
>>
>> Modified: dragonegg/trunk/src/Debug.cpp
>> URL: http://llvm.org/viewvc/llvm-project/dragonegg/trunk/src/Debug.cpp?rev=186952&r1=186951&r2=186952&view=diff
>> ==============================================================================
>> --- dragonegg/trunk/src/Debug.cpp (original)
>> +++ dragonegg/trunk/src/Debug.cpp Tue Jul 23 11:07:59 2013
>> @@ -411,6 +411,8 @@ void DebugInfo::EmitGlobalVariable(Globa
>>     expanded_location Loc = expand_location(DECL_SOURCE_LOCATION(decl));
>>     DIType TyD = getOrCreateType(TREE_TYPE(decl));
>>     StringRef DispName = GV->getName();
>> +  if (DispName.empty())
>> +    DispName = "__unknown__";
>>     if (DECL_NAME(decl)) {
>>       if (IDENTIFIER_POINTER(DECL_NAME(decl)))
>>         DispName = IDENTIFIER_POINTER(DECL_NAME(decl));
>>
>>
>> _______________________________________________
>> llvm-commits mailing list
>> llvm-commits at cs.uiuc.edu
>> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits